Optical networks and the like (e.g., Dense Wave Division Multiplexing (DWDM), Synchronous Optical Network (SONET), Synchronous Digital Hierarchy (SDH), Optical Transport Network (OTN), Ethernet, and the like) at various layers are deploying control plane systems and methods. Control planes provide an automatic allocation of network resources in an end-to-end manner. Exemplary control planes may include Automatically Switched Optical Network (ASON) as defined in ITU-T G.8080/Y.1304, Architecture for the automatically switched optical network (ASON) (February 2012), the contents of which are herein incorporated by reference; Generalized Multi-Protocol Label Switching (GMPLS) Architecture as defined in IETF Request for Comments (RFC): 3945 (October 2004) and the like, the contents of which are herein incorporated by reference; Optical Signaling and Routing Protocol (OSRP) from Ciena Corporation which is an optical signaling and routing protocol similar to Private Network-to-Network Interface (PNNI) and Multi-Protocol Label Switching (MPLS); or any other type control plane for controlling network elements at multiple layers, and establishing connections among nodes. Control planes are configured to establish end-to-end signaled connections such as Subnetwork Connections (SNCs) in ASON or OSRP and Label Switched Paths (LSPs) in GMPLS and MPLS. Note, as described herein, SNCs and LSPs can generally be referred to as services in the control plane. Also, note the aforementioned control planes are circuit-based control planes, e.g., operating at Layer 1(Time Division Multiplexing (TDM)) and/or Layer 0(wavelengths). Control planes use the available paths to route the services and program the underlying hardware accordingly.
In addition to control planes which are distributed, a centralized method of control exists with Software Defined Networking (SDN) which utilizes a centralized controller. SDN is an emerging framework which includes a centralized control plane decoupled from the data plane. SDN provides the management of network services through abstraction of lower-level functionality. This is done by decoupling the system that makes decisions about where traffic is sent (the control plane) from the underlying systems that forward traffic to the selected destination (the data plane). Examples of SDN include OpenFlow (www.opennetworking.org), General Switch Management Protocol (GSMP) defined in RFC 3294 (June 2002), and Forwarding and Control Element Separation (ForCES) defined in RFC 5810 (March 2010), the contents of all are incorporated by reference herein. Note, distributed control planes can be used in conjunction with centralized controllers in a hybrid deployment.
Networks are multi-layered in nature, such as abstracted by the Open Systems Interconnection model of Layers 1 through 7 (L1 -L7). For descriptions herein, an additional Layer 0 is described as the physical photonic/Dense Wavelength Division Multiplexing (DWDM) network, whereas Layer 1 is used for Optical Transport Network (OTN) or other Time Division Multiplexing (TDM) protocols, Layer 2 is used for packet transmission, and the like. For example, with optical networks, a circuit switching layer (L1) (e.g., OTN, Synchronous Optical Network (SONET), etc.) relies on underlying DWDM (L0) with various Reconfigurable Optical Add/Drop Multiplexers (ROADMs). Above the circuit switching layer, packet connectivity such as Ethernet, Internet Protocol (IP), etc. can add to the network hierarchy, e.g., L2 +. In this hierarchy, a server layer is typically responsible for physical connectivity, and a client layer is responsible for fast reroutes, flow control, Quality of Service (QoS), etc.
Packet-Optical Transport Systems (POTS) enable multilayer support of network services. A hybrid service can operate simultaneously at multiple layers, and an exemplary hybrid service can include Ethernet over OTN (as well as over DWDM). In control plane and SDN communications, conventionally, signaling is sent between nodes to an end node which then forwards the signaling through all intermediate nodes towards a destination node. The signaling messages are sent at a single layer, and in the case of transport networks such as with OTN, via OTN signaling through the General Communications Channel (GCC). Conventionally, the OTN layer can establish communications with another OTN node in a network traversing multiple nodes, such as Reconfigurable Optical Add/Drop Multiplexer (ROADM) nodes, using control plane signaling. However, a similar function does not exist in a hybrid Packet and OTN network since control plane signaling will always be terminated on each hop and the L2 control Protocol Data Units (PDUs) can only be generated by a packet control layer. Thus, disadvantageously, for hybrid services, each intermediate node processes and forwards control plane messages, even if the messages were not meant for the intermediate node as may be the case for control plane messages related to Ethernet. That is, conventionally, control planes run on each network element along a path with the specialized handling of control plane messages. There is a need to adapt conventional, multilayer networks to better support hybrid services, such as via POTS or the like.